Recoil-check.



W. A. JOHNSON. i

REGOIL CHECK.

APPLICATION FILED 11111.18, 1911.

Patented Ju1y'30, 1912.

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'WILLIAM' A. JONSQN, 0F CHICAGO, ILLINOIS.

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pecication Letters Patient. Patented J uly 3 0, 1912-.

application sica miren 18,1911. seriai 1ro. e15,212. s

To all whom t mag/lfconce-m:

-Be it known that I, WILLIAM A. JOHN- soN, a citizen 'of the United States, residing at Chicago, in the county of Cook and` State of Illinois, have invented certain new and useful Improvements in Recoil-Checks, of whichV` the ffollowingis a speciticiitionrwn My invention relates to improvements in recoil checks, .and has for its'general ob' ject to provide a'simple, efficient, and practical device wherein a fluid cushionin medium lis used, and the movements o 'said medium are 'valve-controlled by advantageous mechanism.;

As one ,exempliication of my invention, L

drawr, and

Ihavefshown in the accompanyin ing ana'utomobile shock recoil abso in said drawing:

Figure 1 is a side elevation with parts broken' away, showing the complete device;

Fig. 1;Fi`g. 3 is an enlarged sectional detail of the piston valve and contiguous parts; Fig. f1 is an enlar ed detail ofthe valve proper; Fig. 5 is a eta'ill of a spring sleeve; and Fig. 6 is a sectional detail on line 6-6 of Fig. 3.

In the specic exemplication shown, 10 is a cylinderhaving one end closed" by the cap 11, threaded thereon, and preferably providing exterior means for attachmentto one of the two parts whose relative niove connection with the remaining one of the two parts whose relative movements areto be controlled, and at its inne-r end it carries a piston generell indicated at 17 working within thecylin er. The piston rod is l preferably made of tubular stock, to provide'a central guiding bore, 18, closed at its outer end and at its-inner open end en 'larged into a Valve'chamber 19v into which open above the piston 17, suitable ports 20. The piston 17 maybe of any desired form, that herein shown being of ordinary cup fo'rm common in air pumps, mountedlexteriorly on the rod 15 and positioned byy ine 2-2 of nuts 21 v and 22,`the end nut 22 being in the i form of an. apertured capproviding an' annular flange 22 to form a stop `partially 'f overlying the end of the valvechamber 19. [In the present 'form of construction, the piston isifntendedfto compress fluid only on its *outstrokef the-end opening of the'casin'g I ibeing" packed with a body 24 of relatively soft pack-ing, material, constantly main- Qtained under pressure Aby piston 17, so that the pressure Yifs leas.trwhen 'the pistoi'is at the extreme'end .ofits in?VVV .7o its out-stroke, thereby insuring maximum f stroke, Vand increases as the piston Works on packing'pressure when" t he piston is comg pressingv 'the fluidconfined` in the pressure chamber on the outer "side-of the piston.

y 26 indicates a guide rod cent-rally secured to the head.` 11, andf extending guiding bore 18 ofthe piston rod, and'28 indicates a f slide valve of the 'piston-type,

disposed within the valve chamber 1 9 and frictionally engaging the guide rod 26. The lvalve 28 provides a head 29, slidable in the a helical spring 25 interposed between said packing and the.A

into the valve chamber 19. and preferably making i slightly loose fit therein, so that whenit is Vinterposed in front ofA the' ports-20, as in-' dicated in Fig. 3, it mayallow 'slight lea-k- ;age of air through said'- ports. The stem 30 gof the valve is preferably slotted as at 31 to form of the stem an annular series of para 1allel 'spring fingers 32, and these are made Dto exert a clamping action upon the rod 26,' preferably by enveloping said lingers with a spring sleeve 33 of steel. As shown'in Fig. 3, the relation of the valve to 1its chamber is such that when valve stem l30 bottoms upon the shoulder 22" at the open end of the chamber, the head 29 practically closes the ports 20, but it will be apparent that when the valve 28 is lifted. to the top. :of the chamber 19 its head 29 will clear the ports 20 leaving free a. passage through the piston by way of portsl 20 and the open Iended valve chamber 19.

vpletely operative,but asa further refine- ;nient, I provide a limitation valve at the- `inner end of the casing yielding to coact `The device thus far described is comwith thenormally open- -endof the vpiston v Valve chamber to close the vair passage through the pistonwhen thepiston nears the head 11 of the cylinder. Specically, 3 5 indicates a valve of leather or' the like surrounding the guide rod 26, and slidable thereon, supported upon a plate 36 which is yielding-ly maintained at a definite distance from the end of the chamber by a helical spring 37.

- Assuming the opposite attaching devices to be connected one to the spring and one to the frame member of an automobile, the operation of the deviceis as follows: When the piston is driven farther into the cylinder by the relative approach of the vehicle running gear and frame attendant upon a shock or bump, the frictional grip of the valve 28 on the'gnide'rod holds it stationary iuitil the top of the valve chamber 19 forces* it downward. Thus, the ports 20 are opened to permit the free flow of air through the piston, during thewhole of the in-stroke of the piston, or until the end of nut 22 seats against the limitation valve 35, thereby finally to inclose a body of air in the inner end of the cylinder to aid the vehicle spring in checking the further relative appreach4 of the vehicle members, and to prevent the piston from striking the cylinder end. As the recoil takes place between the vehicle members, the piston valve 28 remains stationary in virtue of its frictional grip on the guide rod 26, until the shoulder 22 of nut 22 engages the lower end of the valve stem.- In this position, the valve closes the ports 20 and the out-stroke of the piston is retarded strongly by the resistance of the air chambered above the piston, so that the vehicle' parts quickly come to normal relation without bouncing. The air pressure in the upper portion of the cylinder is gradually relieved by the slight leakage intentionally permitted past the valve head 29, while the vehicle/elements are separating, and as soon as the recoil is checked, the reduced pressure tends to force the piston 'down slightly and then the passage 20-19 is opened again, permitting quick restoration of the pressure on opposite sides of the piston to equilibrium. Thus, the construction described permits they vehicle spring to :1ct in one direction with almost perfect freedom, but interposes a material air-cushioned resistance to the rebound of the load resulting from reaction of the spring after compression.

While I have herein described a single embodiment of my invention for purposes of full disclosure, it will be apparent that numerous changes might be made in the construction without departure from the spirit of my invention and within the scope of the appended claims.

WhatI claim is:

l. In a device of the character described,

the combination of a cylinder, a piston having a passageway therethrough, a valve controlling said passageway, a guide member, and spring means embracing a portionof said valve to give it a friction grip on said guide member.

2. In a device of the character described, the combination of a c linder, a piston therein, a piston rod t erefor having a guiding bore and a valve chamber, and ports opening laterally into said valve chamber between'its ends, a piston-type slide valve in said chamber provided with a head the cylindricalside surfage goflhich coperat with said portsY and/having a limited range of movement to close said ports when at one extreme of movement and to open said ports when at the other extreme of movement, and a guide rod centrally carrled by the cylinder frictionally engaged by said valve.

3. In a device of the character described, the combination of a cylinder, a piston, having a passageway therethrough, a valve controlling said passageway, providing a central bore surrounded by an annular series of spring fingers, and a friction rod carried by the cylinder frictionally engaged by said spring fingers to control the movements of the valve.

4. The combination of a-cylinder, a piston having a passageway therethrough, a valve controlling said passageway providing a central bore surrounded by an annular series of spring fingers, a friction rod carried by the cylinder frictionally engaged by said spring fingers to control the movements of the valve, and a spring band shorter than the fingers surrounding the latter, and movable thereon. y

5. In a device of the character described, the combination of a cylinder, a piston, a

piston rod therefor, said piston having apassageway therethrough, said passageway providing a limited space for travel of a valve, a valve in said space arranged when at one extreme of its travel in said space to close the passageway, and when at the other extreme of its travel in said space to open the passageway, and a stationary part carried by thiI casing entering said passageway and making frictional engagement with said valve to control its relative movement with respect to the valve-containing space.

In testimony whereof I hereunto set my hand in the presence of two witnesses.

WILLIAM A. JOHNSON.

In the presence of- MARY F. ALLEN, W.LINN ALLEN. 

